Method for establishing a telecommunications network for patient monitoring

ABSTRACT

A wireless network having an architecture that resembles a peer-to-peer network has two types of nodes, a first sender type node and a second receiver/relay type node. The network may be used in a medical instrumentation environment whereby the first type node may be wireless devices that could monitor physical parameters of a patient such as for example wireless oximeters. The second type node are mobile wireless communicators that are adapted to receive the data from the wireless devices if they are within the transmission range of the wireless devices. After an aggregation process involving the received data, each of the node communicators broadcasts or disseminates its most up to date data onto the network. Any other relay communicator node in the network that is within the broadcast range of a broadcasting communicator node would receive the up to date data. This makes it possible for communicators that are out of the transmitting range of a wireless device to be apprized of the condition of the patient being monitored by the wireless device. Each communicator in the network is capable of receiving and displaying data from a plurality of wireless devices.

FIELD OF THE INVENTION

The present invention relates to a wireless telecommunications networkthat may be used in the medical industry, and more particularly relatesto a nodal network that has a plurality of node communicators forconveying patient parameters remotely from the site where the patient isbeing monitored. Also disclosed are inventions that relate to the methodof remotely conveying or propagating patient information along thenetwork and the devices used in such wireless telecommunicationsnetwork.

BACKGROUND OF THE INVENTION

To remotely monitor physical parameters, for example blood pressure,arterial oxygen blood saturation (SP02), heart rate, electrocardiogram,etc., of a patient, a sensor is usually attached to the patient, withthe sensor being connected to a transmitter that transmits the patientsignals to a central nursing station. Such transmission is usually byhardwire, and more recently wirelessly. At the nursing station, whichmay either be located in the general ward or in an intensive care unit(ICU) of a hospital, a number of monitors are provided to monitor thepatients in the various rooms. There is always a nurse at the nursingstation who monitors the physical parameters of the different patientsthat are being transmitted from the various patient rooms, in order toobserve the physical well-being of the patients. Such central nursingstation works well in an environment whereby the patients are confinedto their respective rooms, with each of the rooms containing theappropriate transmitter for transmitting the physical parameters sensedby the sensor(s) connected to the respective patients.

There is however a trend in the medical field to incorporate wirelesscommunications to provide mobility for the patient. In the medicalfield, for example in the area of pulse oximetry, one such portabledevice is a finger oximeter with remote telecommunications capabilitiesthat is disclosed in U.S. Pat. No. 6,731,962, assigned to the assigneeof the instant application. The disclosure of the '962 patent isincorporated by reference herein. The '962 device is adaptable totransmit patient data to a remote receiver or monitor. Another pulseoximeter that is capable of communicating with an external oximeter viaa wireless communications link is disclosed in patent publication2005/0234317. The remote device for this oximeter is a display. Anotherwireless pulse oximeter is disclosed in patent publication 2005/0113655.There a wireless patient sensor would transmit raw patient data to apulse oximeter that processes the data and further configures the datato generate a web page, which is then transmitted wirelessly to awireless access point, so that the web page may be downloaded by remotemonitoring stations that are connected by means of a network to theaccess point. Another system that remotely monitors the conditions of apatient is disclosed in patent publication 2004/0102683. The '683publication discloses a patient monitoring device worn by the patient.The patient data collected from the patient is transmitted wirelessly toa local hub. The hub then transfers the data to a remote server by wayof a public or private communications network. The server is configuredas a web portal so that the patient data may be selectively accessed byphysicians or other designated party that are allowed to view thepatient's data.

The current systems therefore are focused to the transmitting of patientdata to a remote hub or access point and are therefore confined to aspecific site from which the patient data may be reviewed remotely. Thenetwork or communications link that are currently used are thus eitherpredefined links that transmit information in a particularcommunications path, or by means of public communications network with aparticular server from which selective access may be granted. Yet all ofthese prior art system are not particularly suited to the abovementioned hospital environment in which there is a need to providemobility for the patients, as well as the need to monitor the multiplepatients. Moreover, there is a need to un-tether the patient from themonitor that is fixed to the room of the patient to provide the patientmore mobility, and yet at the same time, allows the care-giver(s) tocontinue to monitor the physical well being of the patient.

There is therefore a need for a portable device that may be worn by apatient which can wirelessly transmit data collected from a patient.

Further, given the shortage of care-givers, there is a need to reducethe requirement for a particular nurse or care-giver to be stationed atfor example a central nursing station, in order to monitor the physicalparameters of the various patients. It may also be advantageous to havemore than one care-giver who could monitor the different physicalparameters of the various patients. It follows then that there is also aneed to enable a nurse or care-giver, or a number of nurses orcare-givers or other healthcare personnel, to be able to monitorremotely in substantially real time the physical well being of apatient, and/or the various patients in this communications network. Tothat end, There is a need for a communications network that couldreceive the data collected from the various patients, and at the sametime correlate the different data collected with the various patients.To fully enable the remote monitoring capabilities of the network, aneed therefore also arises for a portable device to be carried by eachcare-giver to thereby un-tether the care-giver(s) from any particularcentral monitoring location.

BRIEF SUMMARY OF THE PRESENT INVENTION

The present invention, among its multiple aspects which may themselvesconstitute self standing inventions, attempts to overcome the need for acentral server or hub to which the data collected from the patient isrouted, per taught by the prior art. The present invention thereforeaims to, in the one aspect, provide remote monitoring across a network,for example a peer-to-peer network or a mesh network with adeterministic configuration, so that there is no reliance on a singlehub or access point.

The present invention, in one aspect, more particularly relates to awireless communications network that is adapted for use by medicaldevices and that has an architecture that may be in the form of apeer-to-peer network of medical devices without a network controller.Each of the medical devices may be considered a node of the network,with the medical devices or nodes being time synchronized and thecommunications among the devices scheduled, to thereby eliminate innetwork interference and allow good quality both in terms of thecommunications among the nodes and the types of messages disseminatedamong the devices.

In an embodiment of the instant invention set in an exemplar medicalenvironment, for example oximetry, a patient whose physiologicalparameters or attributes are to be measured has attached to him or her asensor module that has a sensor to measure the physical parameters ofthe patient. The obtained patient data may be routed by the sensor to atransmitter for transmission. Alternatively, the sensor module may initself contain a transmitter for transmitting the measured physicalparameters of the patient. A transceiver may also be provided in thesensor module in the event that bidirectional communications between thesensor module and a remote receiver is desired. The sensor module may bereferred to, in the being discussed medical environment, as a wirelessoximeter sensor. Each of the wireless oximeter sensor may include anoximeter and its associated sensor, as well as a transceiver or radiofor outputting or transmitting the patient data obtained by the sensor.

The receiver that receives the signal output from the sensor attached tothe patient may be a bi-directional communication device referredhenceforth as a communicator that has a transceiver for receiving andtransmitting information or data. At least one memory is provided in thecommunicator for storing the most up to date information that it hasreceived. In addition to the transceiver and the memory, thecommunicator may also have a processor, an user interface, a powercircuit and in the case of it communicating with an oximeter sensor, anoximeter circuit. The communicator is adapted to aggregate informationreceived or collected, so that data from the communicator may bedisseminated or broadcast out toward the network.

There may be a plurality of communicators in the communications networkof the instant invention, with each communicator being considered a nodeof the network. As the network is comprised of a plurality of nodes eachbeing a communicator, the communication of data through the networktherefore is consistent and controllerless. Moreover, as each of thecommunicators is mobile, the topology of the network changes andtherefore the network is topology independent and resembles apeer-to-peer architecture. The size the network depends on the number ofcommunicators or nodes that are in the network. One exemplar network maycomprise from a minimum of two communicators to a maximum of Ncommunicators, or nodes. Each transceiver, or radio, in each of thecommunicators has a broadcast or transmission range of a predetermineddistance, so that the information broadcast from one communicator wouldcover a given transceiving area. Other communicators or nodes within thenetwork that are within the transmission range of another communicatorwould receive the data that is being broadcast from that othercommunicator. Conversely, that other communicator will receive data thatis broadcast from the communicators that are within its own receptionrange. Thus, data may be communicated among the different communicators,or nodes, of the network. There is therefore no dedicated access point,coordinator or controller in the network of the instant invention.

Not all nodes in the network are communicators, as wireless oximeters,or other medical devices, that are meant to be attached to the patientfor monitoring or measuring physical parameters of the patient may alsobe considered as nodes of the network. For the instant invention, suchwireless oximeter, and other types of medical devices that are adaptedto measure or sense physical attributes from a patient, may beconsidered as a sensor node of the network. Alternatively, sensor nodesthat collect information from the patient and transmit the collectedinformation to the network may also be referred to as first type nodesof the network. It follows then that the second type nodes for thenetwork of the instant invention are the communicators that receive,aggregate and broadcast the data received from the patient via the firsttype nodes, i.e., the wireless oximeter sensors. The communicationsprotocol for the different types of nodes, or among the wireless sensorsand the communicators, may be based on the IEEE Standard 802.15.4.

So that the various nodes of the network can communicate with eachother, the devices of the network are time synchronized and follow agiven communications schedule. For synchronization, the nodes of thenetwork each are assigned time slots, with each time slot divided intosubslots. Each of the nodes, or devices, is synchronized by means ofcommunications from its neighbor(s), so that each node transmits dataonly in the time slot allotted to it. The communication schedule iscyclic so that all nodes on the network are scheduled to transmit orbroadcast their stored data, in accordance with the respective assignedslots for the different communicator devices that form the network.

As data is disseminated or propagated from one node to the other nodes,the data is aggregated in each of the nodes that received the data. Theaggregated data is disseminated across the network, so that the messagesbeing propagated across the network are continuously updated.Aggregation takes place in a node when the message received by that nodeis newer than the message previously stored in that node.

In a first aspect, the present invention is directed to a system forcommunicating information relating to physical attributes of a patient.The system includes at least one patient monitoring device associatedwith a patient that has a sensor for detecting at least one physicalattribute of the patient, and at least one transmitter for transmittingpatient data corresponding to the detected physical attribute out to adevice transmission area. There is also included in the system aplurality of communicators each having a transceiver adapted to at leastreceive the data transmitted from the patient monitoring device when itis located within the device transmission area. Each of thecommunicators communicates with other communicators that are within itstransceiving area. For the inventive system, any one of thecommunicators, when located within the device transmission area, isadapted to receive the patient data from the patient monitoring device,and after receipt of the patient data, broadcast the patient data toother communicators that are located within its communicatortransceiving area.

Another aspect of the invention is directed to a system forcommunicating information relating to physical attributes of patientsthat includes multiple patient monitoring devices each associated with aparticular patient. These patient monitoring devices each have sensormeans for detecting at least one physical attribute of the patientassociated with the device and a transmitter for transmitting thepatient data that corresponds to the physical attribute to atransmission area of the device. There is also included in the inventivesystem a plurality of communicators each having a transceiver adapted toreceive patient data transmitted from the patient monitoring deviceswhen located within the respective transmission areas of the patientmonitoring devices. Each of the communicators is adapted to communicatewith the other communicators within its transceiving area. Each of thecommunicators, when located within the transmission area of any one ofthe patient monitoring devices, is therefore adapted to receive thepatient data from the any one patient monitoring device and thereafterbroadcast the received patient data out to its own communicatortransceiving area.

A third aspect of the instant invention is directed to a system fordisseminating information relating to physical attributes of a patientremotely that includes at least one oximeter associated with a patienthaving sensor means for detecting at least the SP02 of the patient. Theoximeter includes at least a transmitter or transceiver to at leasttransmit patient data corresponding to the detected SP02 away from thedevice. The system further includes a plurality of communicators eachhaving a transceiver adapted to receive the data transmitted from thepatient oximeter when located within the transmission range of thepatient oximeter. Each of the communicators is adapted to communicatewith the other communicators, so that when one of the communicators islocated within the transmission range of the oximeter, it would receivethe patient data from the patient oximeter and thereafter broadcast thereceived patient data to the other communicators that are located withinits broadcast range.

A fourth aspect of the instant invention is directed to a communicationsnetwork where information relating to physical attributes of a patientmay be conveyed remotely. The inventive communications network includesat least one wireless sensor associated with a patient for detecting atleast one physical attribute of a patient. The sensor includes at leasta transmitter for transmitting patient data corresponding to thedetected physical attribute away from the sensor. The network furtherincludes a first communicator located within transmission range of thesensor having a transceiver adapted to receive the patient datatransmitted from the sensor and to broadcast the received patient data.The inventive communications network further includes a secondcommunicator in communication with the first communicator but not incommunication with the wireless sensor. The second communicator has asecond transceiver adapted to receive the patient data broadcast by thefirst communicator.

A fifth aspect of the instant invention is directed to a wirelessnetwork having a plurality of nodes for disseminating information ofpatients. The inventive wireless network includes at least a first typenode adapted to be associated with a patient for monitoring the physicalattributes of the patient. The first type node includes a detector thatdetects at least one physical attribute of the patient and a transmitterthat transmits the detected physical attribute of the patient as dataout to the network. There may also be included in the network aplurality of mobile second type nodes not directly associated with thepatient that are adapted to receive signals and/or data from the firsttype node when moved to within the broadcast range of the first typenode. Each of the second type nodes further is adapted to receive thesignals and/or data from other second type nodes and to broadcastsignals and/or data onto the network. The wireless network of thisaspect of the invention allows any one of the second type nodes, whenmoved to within the broadcast range of the first type node, to receivethe patient data output from the first type node, and thereafter tobroadcast the received patient data out to the network so that any othersecond type node located within the broadcast range of the one secondtype node would receive the patient data output from the first typenode.

A sixth aspect of the invention is directed to a wireless network thathas a plurality of nodes for disseminating information of patients. Thisinventive wireless network includes multiple first type nodes eachadapted to be associated with a particular patient for monitoring thephysical attributes of the particular patient. Each of the first typenodes includes a detector that detects at least one physical attributeof the particular patient and a transmitter that transmits the detectedphysical attribute as patient data out to the network. The wirelessnetwork further includes a plurality of mobile second type nodes notdirectly associated with any patient that are adapted to receive signalsand/or data from the first type nodes when moved to within the broadcastrange of any of the first type nodes. Each of the second type nodesfurther is adapted to receive signals and/or data from other second typenodes and to broadcast signals and/or data out onto the network. Whenone of the second type nodes is moved to within the broadcast range ofany of the first type nodes, the one second type node would receive thepatient data output from that first type node. The one second type nodethen would broadcast the receive patient data out to the network so thatany other second type node located within the broadcast range of the onesecond type node would receive the patient data output by the first typenode.

A seventh aspect of the instant invention is directed to a method ofdisseminating information relating to physical attributes of patients.The method includes the steps of: a) associating at least one patientmonitoring device having sensor means and at least a transmitter with apatient; b) detecting at least one physical attribute from the patientusing the sensor means; c) transmitting patient data corresponding tothe one detected physical attribute out to a device transmission area;d) providing a plurality of communicators each having a transceiveradapted to receive data transmitted from the patient monitoring deviceand to broadcast data out to a communicator transceiver area; e)locating one of the plurality of communicators within the devicetransmission area of the one patient monitoring device to receive thepatient data; and f) broadcasting from the one communicator the receivedpatient data to its communicator transceiver area so that othercommunicators that are not located within the device transmission areabut are located within the transceiver area of the one communicator areable to receive the patient data transmitted from the one patientmonitoring device.

An eighth aspect of the instant invention is directed to a method ofcommunicating information relating to physical attributes of patientsthat comprises the steps of: a) providing multiple patient monitoringdevices each having sensor means for detecting at least one physicalattribute from a patient and a transmitter for transmitting the detectedphysical attribute; b) associating the multiple patient monitoringdevices with corresponding patients; c) providing a plurality ofcommunicators each having a transceiver adapted to receive patient datatransmitted from any one of the patient monitoring devices and tocommunicate with other communicators; d) locating any one of thecommunicators to the transmission area of one of the patient monitoringdevices being used to detect the physical attributes of its associatedpatients; e) effecting the one communicator to receive the transmittedpatient data from the one patient monitoring device; and f) effectingthe one communicator to broadcast the received patient data out to itscommunicator transceiving area.

A ninth aspect of the invention is directed to a method of disseminatinginformation relating to physical attributes of the patients remotelythat comprises the steps of: a) associating with a patient at least oneoximeter having sensor means for detecting at least SP02 of the patient,the oximeter including a transceiver or at least a transmitter totransmit patient data corresponding to the detected SP02 away from thedevice; b) providing a plurality of communicators, each of thecommunicators having a transceiver adapted to receive data transmittedfrom the patient oximeter when located within the transmission range ofthe patient oximeter, the each communicator further is adapted tocommunicate with other communicators; c) locating one of thecommunicators within the transmission range of the patient oximeter sothat the one communicator receives the patient data from the patientoximeter; and d) broadcasting from the one communicator the receivedpatient data to the other communicators that are located within thetransmission range of the one communicator.

A tenth aspect of the instant invention is directed to a method ofconveying information relating to physical attributes of a patientremotely in a wireless communications network environment that has aplurality of transmitting and receiving devices. The method comprisesthe steps of: a) associating at least one wireless sensor with a patientfor detecting at least one physical attribute of the patient, the sensorincluding at least a transmitter; (b) transmitting patient datacorresponding to the detected physical attribute out onto the network;c) locating a first communicator within the transmission range of thesensor, the first communicator having a transceiver adapted to receivethe patient data transmitted from the sensor; d) broadcasting from thefirst communicator the received patient data out onto the network; ande) establishing communication between a second communicator and thefirst communicator, the second communicator not in direct communicationwith the wireless sensor, the second communicator having a secondtransceiver adapted to receive the patient data broadcast by the firstcommunicator.

An eleventh aspect of the invention is directed to a method fordisseminating information of a patient in a wireless network having aplurality of nodes. The method comprises the steps of: a) associating atleast one first type node with the patient for monitoring the physicalattributes of the patient, the first type node including a detector thatdetects at lease one physical attribute of the patient and a transmitterthat transmits the detected physical attribute as patient data out tothe network; b) locating a plurality of second type nodes not directlyassociated with the patient in the network, each of the second typenodes adapted to receive signals and/or data from the first type nodewhen moved to within the broadcast range of the first type node, each ofthe second type nodes further is adapted to receive signals and/or datafrom other second type nodes and to broadcast signals and/or data out tothe network; c) moving one of the second type nodes to within thebroadcast range to the first type node to receive the patient dataoutput from the first type node; and d) broadcasting from the one secondtype node the received patient data out to the network so that any othersecond type node located within the broadcast range of the one secondtype node would receive the patient data output by the first type node.

A twelfth aspect of the invention is directed to a method ofdisseminating information of a patient in a wireless network environmentthat has a plurality of nodes. The method comprises the steps of: a)associating each of multiple first type nodes with a particular patientfor monitoring the physical attributes of the particular patient, eachof the first type nodes includes a detector that detects at least onephysical attribute of the particular patient and a transmitter thattransmits the detected physical attribute as patient data out onto thenetwork; b) positioning in the network a plurality of second type nodesnot directly associated with any patient; c) configuring each of thesecond type nodes to receive signals and/or data from the first typenodes when moved to within the broadcast range of any of the first typenodes and to receive signals and/or data from other second type nodeswhen within broadcast range of the other second type nodes, and tobroadcast signals and/or data out to the network; d) locating one of thesecond type nodes to within the broadcast range of any of the first typenodes to receive the patient data output from any of the first typenodes; and e) broadcasting thereafter from the second type node thereceived patient data out to the network so that any other second typenode located within the broadcast range of the one second type nodewould receive the patient data output by the first type node.

BRIEF DESCRIPTION OF THE FIGURES

The different aspects of the invention will become apparent and will bebest understood by reference to the following description of theinvention(s) taken in conjunction with the accompanying drawings,wherein:

FIG. 1 a is an exemplar architecture of the system of the presentinvention that shows an interconnected network such as for example apeer-to-peer network;

FIG. 1 b is a simplified view of a node of the network, showing the nodebeing a medical device including a radio in a medical instrumentationenvironment;

FIG. 2 is an exemplar network that combines the peer-to-peer network ofFIG. 1 a with wireless medical devices such as wireless oximeters thatare connected to the network;

FIG. 3 is an exemplar simple block diagram of a communicator, in thisinstance a medical communicator, that forms a node of the network of theinstant invention;

FIG. 4 is yet another block diagram in more detail of the communicator,or a relay node, of the network of the instant invention;

FIG. 5 is a block diagram of the wireless oximeter sensor, or the sensornode, that forms part of the communication network of the instantinvention;

FIG. 6 shows a communicator of the instant invention, acting as a relaynode, being communicatively linked to a wireless oximeter, or a sensornode, of the instant invention network;

FIG. 7 is a block diagram showing a sensor, in this instance an oximetersensor, being hardwire connected by a cable to a communicator of theinstant invention, so that the communicator may act as a transmitter forthe sensor;

FIG. 8 is an illustration of an exemplar system of the instant inventionwhereby a patient sensor is communicatively linked to a communicator,which in turn is communicatively linked to other communicators of thenetwork;

FIG. 9 is an exemplar illustration of the time slots for schedulingcommunications among the various communicative devices of the network;

FIG. 10 shows exemplar types of messages that communicate among thevarious communicative devices, or nodes, of the network;

FIG. 11 is an exemplar illustration of how the messages are aggregatedand broadcast from one node communicator to another node communicator inthe network;

FIG. 12 is an exemplar illustration of the interactive communicationsbetween an exemplar communicator, or relay node, and a wirelessoximeter, or sensor node, of the network;

FIG. 13 is a block diagram showing in more detail the various componentsof a communicator of the instant invention;

FIG. 14 is an exemplar circuit schematic of the inventive communicatorof FIG. 13;

FIG. 15 is a diagram showing in more detail the various components of anexemplar wireless oximeter or sensor node of the instant invention;

FIG. 16 is an illustration of the major states of the radio transmitterthat may be used in the wireless oximeter sensor of the instantinvention;

FIG. 17 is a flow diagram illustrating the operational steps theinventive communicator processes to receive information;

FIG. 18 is a flow chart that illustrates the process undertaken by theradio transmitter in the communicator, and also in the wireless sensor,to transmit data;

FIG. 19 is a flow diagram that illustrates the process of data beingaggregated in a communicator;

FIG. 20 is a flow diagram illustrating the process for updating data inthe memory of a communicator;

FIG. 21 is a flow chart illustrating the process of a communicatorbroadcasting the message that has been updated in its memory; and

FIG. 22 is a flow diagram illustrating the operational processing stepsof a wireless oximeter, or a sensor node, of the instant invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 a and 1 b, a communications network, in theconfiguration for example of a peer-to-peer network, is shown. For theexemplar wireless network 2 shown in FIG. 1 a, there are four nodes 1-4,as well as a node N that signifies that the network can have N number ofnodes. For the embodiment of the invention shown in FIG. 1 a, it ispresumed that each of the nodes shown may be represented by node 4 ofFIG. 1 b in that each of the nodes of the network may be a medicaldevice that includes a radio, which may be a transmitter or transceiver.The medical device may be any one of a number of devices that monitor ormeasure physical attributes or parameters of a patient or subject. Suchmedical devices include, but are not limited to, oximeters, heart ratemonitors, capnographs or CO2 monitors, pumps that connect to the patientand other devices that monitor particular physical attributes of apatient. For example, in the case of a pulse oximeter, the oxygen levelof arterial blood (SPO2) of the patient is monitored and/or measured. Inthe case of a capnograph, the CO2, ETCO2 (End Tidal CO2) and respirationrate are monitored and/or measured. Some of these medical devices may becombined. For example, the assignee of the instant application currentlymarkets a non-radio product that is a combination of an oximeter and acapnograph under the trade name CAPNOCHECK®. For the instant invention,such combination device may be fitted with a radio so as it could act asa node of the inventive network.

The radio portion of device 4 may be a transceiver, or at least atransmitter, that operates under a conventional standardtelecommunications protocol such as for example the IEEE Standard802.15.4, so that data may be transmitted from the device out to a givenbroadcast or transmission area of the device. As will be discussedlater, there are additional components in device 4. For the time being,suffice it to say that the communications network of FIG. 1 a is anetwork that may comprise a peer-to-peer network of devices, medical orotherwise, that can communicate among each other without a hub or acentral network controller.

As will be discussed in greater detail later, the nodes of the networkare time synchronized and the communications among the nodes arescheduled, so that network interference that may affect thecommunications among the nodes is substantially eliminated. Also,particular message types are provided to enhance the quality ofcommunication among the nodes. The particular architecture of thenetwork as shown in FIG. 1 a further enables the dissemination of datato all of the nodes by the data being broadcast. By a process ofaggregation performed in each of the nodes, the most recently obtaineddata is broadcast by the nodes so that the integrity of the data beingcommunicated is enhanced. This results in the data being communicated orpropagated throughout the network to be predictable, consistent, andwithout any need for a central controller or hub.

The topology of the network can vary and not be constrained by aparticular configuration, as the size of the network may range by aminimum of 2 to a maximum of N nodes. As each of the nodes, which may bein the form of a medical device, is mobile, the topology of the networkvaries in accordance with the respective locations of the nodes at anyone particular time. Given that each of the nodes has its own radiotransmitter, each of the nodes is capable of broadcasting to apredetermined transmission range. Thus, all nodes within the broadcastor reception range of a given node can be in communication therewith.Further, as communication is not controlled by a specific node orcentral hub, the communications among the nodes are not restricted to aparticular access point.

As shown in FIG. 2, the network of FIG. 1 a is communicatively connectedto a number of wireless oximeters, or the other medical devicesdiscussed above. The nodes per discussed above in the FIG. 1 a networkare referenced as N1-NN and may also be referred to as communicatorsCO1-CON. For the FIG. 2 illustration, wireless oximeters O1, O3 and ONare communicatively connected to communicators CO1, CO3 and CON,respectively. For the instant invention, the wireless oximeters, orother medical devices per discussion above, that monitor physicalparameters of the patient, may be referred to as a first type of nodes,while the communicator CO1-CON may be referred to as a second type ofnodes N1-NN, of the network. The wireless oximeters may further bereferred to as sensor or sensing nodes while the communicators mayfurther be referred to as relay or propagating nodes.

The wireless oximeters are devices or modules that may be worn by apatient, for example on the finger, with a sensor built therein todetect the SP02 of the patient. An example of such wireless oximetermodule is disclosed in U.S. Pat. No. 6,731,962, assigned to the assigneeof the instant invention. The disclosure of the '962 patent isincorporated by reference herein. Other types of oximeter sensors thatmay be worn by or associated with a patient include the reflective typethat may be attached to the forehead or other substantially flatsurfaces of the patient, or an ear type that is adapted to clip onto theear of the patient. The inventors have found that the inventive networkoperates efficiently even when 16 wireless oximeters are connected tothe network. This is not to say that the FIG. 2 network. may not have asmaller number of oximeters, for example 1, or more than 16 oximeters.Similarly, it was found that the preferable number of communicators ornodes in the system or network should be between 2 to 32, with thenumber of communicators or nodes greater than 32 being possible byadjustment of the time slots and time synchronization of the system, aswill be discussed later.

With reference to FIG. 3, a communicator 6 of the instant invention isshown to include a host processor 8 that executes a program 10 stored ina memory, not shown. The program enables processor 8 to operationallycontrol the oximeter circuit 12, which interfaces with an externaloximeter that is either coupled to the communicator by hardwire such asfor example a cable, or by radio, so as to produce digital oximetry datafor processing by processor 8. An user interface 14, also connected toprocessor 8, enables the communicator to interface with the user. Theuser interface may comprise a display, for example a LCD display, aninput source for example a keypad, and an audio circuit and speakersthat may be used for alarms. Providing the power to the communicator 6is a power circuit 16 that may include a battery, or DC input and otherwell known power analog circuits, so that regulated power may be routedto all of the active circuits of the communicator. An electricalinterface 18 is also provided in communicator 6. Such electricalinterface may comprise an electrically conductive communications portsuch as for example a RS-232 port, a USB port, or other similarinput/output (IO) port that allows interfacing to and from thecommunicator. To transceive data to and from the communicator, there isprovided a radio transceiver that wirelessly transceives or communicatesdata between the communicator and other communicators, as well asbetween the communicator and a sensor device such as the wirelessoximeter sensor shown in FIG. 2, or other sensor devices, medical orotherwise, that are adaptable to transmit data wirelessly.

FIG. 4 elaborates on the various components of the communicator 6 shownin FIG. 3. For example, the user interface 14 is shown to include adisplay, a keypad, a speaker and an analog to digital (A/D) circuitdesignated by “analog”. As is well known, the AND circuit converts theanalog input into a digital signal, which is sent to the host processor8. The power component 16 of the communicator as shown in FIG. 4includes a battery, the DC input for charging the battery, aconventional analog power circuit and a digital circuit that allows thepower component 16 to communicate with host processor 8. The powerprovided by the power component is routed to all of the active circuitsof the communicator. The electrical interface component 18, as wasmentioned previously, has one or both of the RS-232 and USB ports, orother interfacing ports that are conventionally used. The oximetercomponent 12 has the analog circuit for analyzing the analog signalsreceived from the patient sensor, a memory program that stores theoperational functions for the oximeter component, and a microprocessorthat processes the data received from the patient to produce digitaloximetry data, which is then communicated to the host processor 8. Aswas noted earlier, a memory program 10 in the host that encompassesprocessor 8 provides the operational instructions to processor 8 for theoverall operation of the communicator. The last major component incommunicator 6 is the radio 20, which includes a radio IC module, amemory stored program that controls the functioning of the radiotransmitter, the analog circuits for controlling the operations of theradio and the antenna that allows the radio transceiver to transmit andreceive signals to and from the communicator.

A wireless oximeter device that forms the sensor node of the network isshown in FIG. 5. The wireless oximeter 22 is shown to include a sensorcomponent 24. Such component is conventional and includes two LEDs thatoutput lights of different frequencies to a digit or some other areasuch as the forehead of a patient, and a detector that detects the lightthat passes through or reflected from the patient. Also included inwireless oximeter 22 is an oximeter circuit 26 that includes aprocessor, an analog circuit that analyzes the waveform signals detectedfrom the patient and a memory that stores the program to instruct theanalog circuit to analyze the incoming signals from the patient andconverts it into oximetry data. The operation of the sensor 24 is alsocontrolled by oximeter circuit 26. Interfaced to and workingcooperatively with the oximeter component 26 and/or the sensor component24 is a radio component 28 that includes an antenna, a program stored ina memory, an analog circuitry that operates the radio IC module and anantenna that transmits the oximetry data of the patient to thecommunicator. Power component 30 includes the battery power source andthe conventional analog power circuitry that supplies power to the othercomponents of the wireless oximeter. In the network of the instantinvention, per shown for example in FIG. 2, the wireless oximeter deviceof FIG. 5 transmits collected patient data to the communicator(s) thatis/are within its broadcast range, or transmission area.

FIG. 6 shows in more detail the interaction of a wireless fingeroximeter device with a communicator of the instant invention. Here awireless communications link 32 is established between communicator 6and the wireless oximeter 22. As shown, the radio transceiver ofcommunicator 6 communicates with the radio transmitter of oximeter 22,so that the oximeter data obtained from the patient by sensor 24 is sentto communicator 6, which may then relay the information by broadcastingit out to its transceiver area. It should be noted that communicator 6would receive the data from oximeter 22 only if it is within thetransmission area or broadcast range of the oximeter device. For theFIG. 6 embodiment, when the oximeter circuit in the wireless oximeter 22is actively analyzing and converting the patient data, the oximetercircuit in communicator 6 may not be since the patient data is beingtransmitted from oximeter device 22 to communicator 6. The signal beingtransmitted from oximeter device 22 to communicator 6 is in mostinstances a digital signal. However, there may be instances where rawdata may be sent directly from the oximeter device to the communicator,if it is desirable to eliminate the analog to digital circuitry in theoximeter and also reduce the processing power from the oximeter. Inother words, raw data may be sent from an oximeter device to acommunicator, if necessary, so that the communicator may perform theprocessing that converts the raw data into the required oximetry data.

In place of the wireless finger oximeter device 22 shown in FIG. 6, theinstant invention is also adapted to be used with a conventionaloximeter sensor, such as 34 shown in FIG. 7. There, a conventionaloximeter sensor that has the light source and the detector necessary formeasuring the SP02 of the patient is connected by means of a cable 36 toa communicator of the instant invention. This may be effected by matingthe electrical connector of the sensor to the port that is a part of theelectrical interface 18 of communicator 6. The signals received from thepatient are then processed and stored, and then broadcast out by thecommunicator to its transceiving area. In this embodiment, communicator6 acts as the transmitter of the patient monitoring device by workingcooperatively with the oximeter sensor. Moreover, as it has to be withincable distance from oximeter sensor 34, communicator 6 is locatedfixedly relative to the oximeter sensor and proximate to the patient.

FIG. 8 shows an ad hoc mesh communications network of the instantinvention where a wireless oximeter sensor device 22, with the sensorpossibly attached to a digit of a patient, not shown, being incommunication with a communicator 6 a. Communicator 6 a in turn is incommunication link with communicator 6 b and communicator 6 c. Bothcommunicators 6 b and 6 c are in communication link with communicator 6d. Communicator 6 d is also communicatively linked to communicator 6 e.

As further shown in FIG. 8, each of the communicators has a display 24that is capable of showing the data of multiple patients. For theexemplar communicators of FIG. 8, both the SP02 and the heart rate ofthe patient(s) are shown on displays 26 a and 26 b, respectively.Further, there are shown on each of the displays of exemplarcommunicators 6 b to 6 e five sets of data, with each set of datarepresenting a particular patient. Although data representing fivepatients is shown in the exemplar communicators of FIG. 8, it should beappreciated that a smaller or a greater number sets of patient parameterdata may also be displayed by each of the communicators. Furthermore, itshould be appreciated that if the communicators of FIG. 8 were devicesother than oximeters as mentioned supra, then the display of each ofthose communicators may display patient data that represents otherpatient attributes, such as for example CO2 and respiration rate in thecase where the devices are CO2 monitors or combined CO2 monitor andoximeter devices.

For the wireless oximeter sensor 22 that is communicatively connected tocommunicator 6 a, the physical parameter measured or sensed from thepatient 1 may be sent as an oximeter data message data file, 96 byte forexample, to communicator 6 a. Upon receipt of the data file fromoximeter device 22, communicator 6 a stores the data file for patient 1as P1 in its remote data display RDD table 28 a. The patient 1previously stored data in the memory of communicator 6 a is replaced orupdated by the latest data from patient 1. The RDD table 28 a for theexemplar communicator 6 a is shown to have a capacity that can storedata of a plurality of patients, for example from patient P1 to patientPN. An exemplar approximately 18 byte memory may be reserved for each ofthe patients in the memory store of the communicator. Multiple tablesmay be stored in each of the communicators, so that patient data thatwere received at different times may actually be kept and compared withthe latest information for an aggregation process that will be laterdescribed in greater detail. The additional exemplar tables 28 b and 28c for the communicator 6 a are shown in FIG. 8.

The interactions between wireless oximeter 22 and communicators 6 beginswhen wireless oximeter 22 transmits a signal representing at least onephysical attribute of the patient, for example the patient's SP02, awayfrom the oximeter to a predetermined transmission range, i.e., thesensor's transmission area. For the FIG. 8 exemplar network, thewireless oximeter 22 may be considered the sensor node. As illustratedby communications link 30 a of the FIG. 8 network, communicator 6 a islocated within the transmission area or zone of wireless oximeter 22.Thus, when wireless oximeter 22 outputs the patient data sensed frompatient 1, communicator 6 a would receive the patient data beingtransmitted. Upon receipt, the patient data may be stored in a RDDtable, for example 28 a, as patient data P1. If there was prior P1 datafor patient 1, this prior data is replaced by the just received data inthe RDD table. The stored data may be displayed on display 24 ofcommunicator 6 a as the SP02 and/or pulse rate of the patient. Note thatthe patient data may also be displayed, analyzed, conductivelycommunicated, and/or stored for trending, RDD or high speed application.

As further shown in the exemplar FIG. 8 network, communicator 6 a hasestablished communication paths with communicator 6 b and communicator 6c via communication links 30 b and 30 c, respectively. As was discussedpreviously, each of the communicators of the instant invention has itsown radio transceiver, so that each communicator is adapted to receivesignals from both wireless oximeters or other medical sensors and othercommunicators, so long as it is within the transmission range of thosesensors and/or communicators. Conversely, each of the communicators isadaptable to broadcast a signal out to a predetermined broadcast range,or its transceiving area. Thus, for the exemplar network of FIG. 8, aseach of communicator 6 b and 6 c is within the transceiving area ofcommunicator 6 a, those communicators each are in communication withcommunicator 6 a.

For the exemplar network of FIG. 8, upon receipt of the patient P1 datafrom wireless oximeter 22, after storing the received data in its RDDtable 28 a, communicator 6 a broadcasts this latest P1 data out to itstransceiving area. Communicators 6 b and 6 c, each being within thetransmitting range of communicator 6 a, receive the same data of patientP1. Each of those communicators 6 b and 6 c then updates its own RDDtable, and may display the latest patient P1 data on its display, sothat the holder of those communicators could see the physicalparameters, in this instance, the SP02 and pulse rate, of patient P1.Each of communicators 6 b and 6 c then transmits the latest patient P1data out to their respective transceiving areas. Note that each ofcommunicator 6 b and 6 c is shown not to be in direct communicationslink with wireless oximeter sensor 22.

As communicator 6 d happens to be in the transmission range of bothcommunicators 6 b and 6 c, it receives the data of patient P1 from eachof those communicator via communication links 30 d and 30 e,respectively. In this scenario, as the patient P1 data is the same fromboth communicators 6 b and 6 c, any updating of the data relating topatient P1 results in the same data being updated in the RDD table ofcommunicator 6 d. However, in another scenario where the communicationsschedule between communicators 6 b and 6 d is substantially differentfrom that between communicators 6 c and 6 d, it may be that the datafrom the same patient received by communicator 6 d from communicators 6b and 6 d may differ due to the propagation delay of the patient dataalong the respective communications links. In that case, the laterpatient data is stored as the patient data in communicator 6 d. Toprevent conflict in the event that the transmission of data frommultiple nodes takes substantially the same amount of time, a timeslotted schedule communication protocol, which will be discussed later,is provided for the network of the instant invention. The last node inthe exemplar network of FIG. 8 is communicator 6 e, which is incommunications range with communicator 6 d via communication link 30 f.Communicator 6 e is not in communication range with any of the othercommunicators or the wireless oximeter sensor 22. With the instantinvention, even though communicator 6 e is located remotely from sensor22, the holder of communicator 6 e nonetheless is able to monitor thephysical parameter of patient 1 due to the propagation of data, or datahop, of the RDD messages across the communicator nodes of the network.

Although only one wireless oximeter sensor 22 is shown in the exemplarnetwork of FIG. 8, it should be appreciated that there might be multiplewireless oximeter sensor devices linked communicatively along thenetwork, so that different communicators of the network may transmitpatient information to other communicators communicatively connectedthereto. As a result, data of multiple patients may be displayed on eachof the communicators. This is illustrated by the respective displays 24of communicators 6 b, 6 c, 6 d and 6 e of the FIG. 8 network where fivesets of data, each corresponding to a particular patient, are displayedon each of those communicators. The users or operators of thosecommunicators may each therefore be able to monitor the physicalparameters of a number of patients, even though they may not be in thevicinity of any one of those patients. Thus, for the network of theinstant invention, so long as a remote communicator node is within thebroadcast range of another communicator node that in turn had received,via possibly other communicator nodes, the data from a patient, thatremote communicator node would also be in receipt of the same patientdata and can therefore monitor remotely the well being of that patient.

To prevent conflict among the various nodes of the network of theinstant invention, a time slotted scheduled communication protocol ismandated. To that end, each of the devices, or nodes, of the network hasone slot of a given time period to transmit its data. This time slottedschedule communications protocol is illustrated in FIG. 9. As shown, anumber of slots, for example slots S1 to S10, are provided in theexemplar time period of FIG. 9. The number of slots may correspond tothe number of communicator devices in a particular network. Thus, if thenetwork were to include 16 devices, then there would be 16 slotsprovided in the time period. The time periods are repeated so thatcommunications among the various devices in the network are scheduled.Predictable and reliable network communications result.

For each device, the time slot assigned thereto enables the device totransmit multiple messages exclusively at that given time slot. Forexample, for the exemplar network of FIG. 8, slot S1 may be assigned tocommunicator device 6 a, slot S2 to communicator 6 b, slot S3 tocommunicator 6 c, slot S4 to communicator 6 d and slot S5 tocommunication 6 e. Thus, communicator 6 a would transmit at time slotS1, communicator 6 b at time slot S2, communicator 6 c at time slot S3,etc. For the exemplar network of FIG. 8, it may not be necessary to have10 slots for each time period. One possible way of assigning each devicea particular slot is for the operator of the facility that the networkis located, for example an ICU ward in a hospital, to have programmedinto the devices their respective slots. Another possible way is for theoperator of the network to assign the devices the different slots. Thevarious devices in the network are synchronized to the radio frequency(rf) transmissions.

There is a fair amount of data that needs to be transmitted in pulseoximetry, including wireless oximetry. In addition to the number ofdevices in the network, the number of messages may be selectivelyoptimized for each of the slots. In the communications protocol of FIG.9, it is assumed that there might be six types of messages that aretransmitted at their assigned slots by each of the relay node devices.These messages are in the form of message packets and are illustrated inFIG. 10. In FIG. 9, the messages (M) are labeled, with M1 correspondingto the first message NWK and M6 corresponding to the last message WS.Message M1, the NWK message, refers to a node overhead informationmessage, or the “network overhead information”. Message M2 is the RDD(remote data display) message that carries the data stored in the RDDtable in the memory of the communicator and, once updated, may bedisplayed by the communicator. Messages M3 and M4 are the HS1 (highspeed 1) and HS2 (high speed 2) messages that flood or broadcast data,when needed, to the other node devices in the network.

To illustrate with reference to the FIG. 8 exemplar network, if thepatient data received from the patient (P1) indicates to communicator 6a that the data from the patient is outside of a predetermined specifiedor acceptable range, then communicator 6 a would go into an alarm modein which an alarm is set off, so that the user of communicator 6 a knowsthat there is something amiss with patient P1. At the same time, toovercome the bandwidth limitations of the network, by means of HS1and/or HS2 messages, communicator 6 a floods the network with alarmmessages in order to reach the other communicators in the network, sincethis may be an emergency situation where the people who are carrying theother communicators should be notified. Thus, by sending HS1 and HS2messages, the operators or medical personnel of communicators 6 d and 6e, who are not in direct communications link with the wireless oximetersensor 22, are nonetheless notified of the alarm condition for patient(P1) so that appropriate action, if any, may be taken by thosehealthcare personnel. Also, the HS1 and/or HS2 messages may beselectively used to broadcast, upon request by a user, measured physicalattribute(s) at a high rate to a remote communicator. The user mayeither be the person associated with the communicator that is totransmit the data, or the person associated with the remote communicatorto which the data is to be transmitted. In the event that the request touse the HS1 and/or HS2 messages were to come from the remotecommunicator, a remote request first has to be received and recognizedas such by the transmitting communicator.

The next message M5 (CTR) is a control message from the communicator toits dedicated wireless sensor, which is identified by message M6 WS(wireless sensor). This is required because a wireless sensor may nothave the user control mechanisms required to configure the integralradio and oximeter. Furthermore, a communicator node in the network maynot necessarily be in direct communications link with its dedicatedsensor. For example, it may be that the carrier of communicator 6 e isin fact the responsible nurse for the patient who is connected towireless oximeter sensor 22 in the FIG. 8 exemplar network. And thereason that communicator 6 e is not in the vicinity of wireless oximetersensor 22 may be that the nurse had to take care of another patient andaccordingly had moved out of the transmission range of wireless oximetersensor 22. Yet the nurse nonetheless is able to continuously monitor thephysical parameters, for example the SP02 of patient P1 due to therelaying of the patient P1 data from the other communicators of thenetwork. Message M6 therefore identifies to the other communicators thatwireless oximeter sensor 22 is the dedicated sensor for communicator 6e. Each communicator may also control the operation of its dedicatedwireless oximeter, if the wireless oximeter is adapted to wirelesslycommunicate bidirectionally, by sending a M5 control message CTR, whichis relayed by the other nodes in the network to the wireless oximeteridentified by the WS message.

With the time slotted scheduled communications protocol shown in FIG. 9,the communications among the various devices of the network becomepredictable and reliable. Accordingly, the protocol provides adeterministic approach for the instant invention system or network, asthe processes for the various nodes are synchronized. Moreover, thesystem is deterministic in that each time slot is assigned to aparticular device, so that each device may be able to listen to theother devices when it is not its time to “talk”; and when it is thedevice's turn to “talk”, the other devices of the network would listen.In other words, each of the devices of the network has been assigned orallotted a given time period to communicate or disseminate informationto the other devices of the network, without any central controllermandating the various devices what to transmit and when to transmit.

The message packets of the message types of FIG. 9 are assigned asufficient size, for example 96 bytes, so that all necessary data may becarried in those message packets for propagation across the network. Themessage types and the respective flows of those messages across thenetwork are shown in more detail in FIG. 10. There, communicator isdesignated “CO”.

FIG. 11 illustrates how the remote data display messages are aggregatedand broadcast or flooded to the various relay nodes or communicators inthe system and network of the instant invention. Here it is assumed thatthere are multiple communicators (CO1, CO2 to CON) in the network, witheach of the communicators transmitting its RDD message out to a giventransceiving range, or broadcast range. As shown, communicator CO2 iswithin the broadcast range of communicator CO1 and communicator CON isin communication range with at least communicator CO2. To preventconfusion and to enhance understanding, for the discussion of FIG. 11,“RDD” may refer to a memory table in each of the communicators and alsoa message when it is transmitted from one node communicator to anothernode communicator.

Communicator C01 has in its memory a local data store that stores theRDD message as RDD table 32, which communicator C01 had incorporatedtherein the information it received, either directly or indirectly, froma wireless oximeter. For RDD table 32, “Node” 32 a refers to the nodes,both sensor and communicator, of the network, the “Time” 32 b refers tothe time stamp of when the message was recorded in the node, and the“Data” 32 c refers to the kind of data that was transmitted from thenode and received by the communicator. Thus, the RDD table incommunicator C01 has stored therein data from a number of nodes (1, 2 toN) each having corresponding data (x1, x2, xN) with a given time stamp(t11, t21 to tN1), respectively. The RDD table 32 from communicator C01is broadcast by the radio transceiver of the communicator to itstransceiving range and is received as RDD message 32′ by communicatorCO2.

Communicator CO2 also has a previously stored RDD table that has anumber of sets of data from the various nodes, per shown by RDD table34. An aggregation process next takes place in communicator CO2 in thatthe data received from communicator CO1, i.e., from RDD message 32′, iscompared with the prior stored data in RDD table 34. As an illustration,the previously stored information from node 1 is “t10” in RDD table 34,whereas the information for node 1 in RDD message 32′ has a time stamp“t1”. This means that the information relating to node 1 is more recentin RDD message 32′. As a consequence, the data for node 1 is updated to“x1” and is stored in the new RDD table 36. The same aggregation processtakes place with the information relating to node 2. For that node,insofar as the time therefor in RDD table 34 is “t22” whereas the timefor node 2 in RDD message 32′ is “t21”, the data that is stored in RDDtable 34 is judged to be the more recent data. Accordingly, the data“y2” in RDD table 34 is copied to RDD table 36. The same aggregationprocess repeats for the remainder nodes in RDD table 34 by comparing itspreviously stored data with those in RDD message 32′. Once the data inthe RDD table 34 has all been compared and if needed updated, theupdated RDD table 36 is broadcast as RDD message 36′ by communicator CO2out to its transceiving area.

RDD message 36′ is received by communicator CON as RDD table message36′. The same aggregation process then takes place in communicator CONwhereby the information in RDD message 36′ is compared with thepreviously stored information in RDD table 38 for generating an updatedRDD table 40. For the example illustration in FIG. 11, the data for node1, as received by communicator CO1, is relayed to communicator CON andupdated in its RDD table 40. Further, the data for node 2, as reflectedin RDD table 40 of communicator CON, is updated from the data previouslystored in RDD table 34 of communicator CO2.

In a system where all of the communicators are within range of all ofthe other communicators, there would be minimal latency in terms of themessages transmitted and received. However, in practice, such often isnot the case as shown in exemplar FIG. 8, so that there is always apropagation delay in terms of the messages that are being broadcast fromone communicator to the next one, as the RDD messages would “hop” fromone communicator node to the next communicator node, in order topropagate across the network. Even though only RDD messages aredisclosed so far as being propagated across the network, it should beappreciated that messages aside from or in addition to RDD messages mayalso be disseminated or propagated across the network from node to node.For example, the communicators have built-in alarm functions, so that ifthe physical parameter(s) measured from a patient exceeds or falls belowrespective upper and higher limits, i.e., outside predetermined safetylimits, the alarm is triggered to warn the user of the communicator thatsomething may be amiss with the patient. Another aspect of the instantinvention is that instead of RDD messages, only an alarm signal ispropagated or flooded across the network to warn the various people,medical personnel or otherwise, equipped with communicators that aparticular patient may be in distress.

So that additional information may be propagated across the network, thecommunicators each may be fitted with a text messenger chip so that itsdisplay may be actuated to a text mode to receive text messages that mayaccompany the alarm, which may be a sound of a given frequency orloudness or a flashing screen for example. The text message may bespecifically directed to a given communicator, or may be broadcast orflooded to all communicators along the network. The communicator of theinstant invention is therefore adapted to be used as a pager that caneither simply receive an alarm from a particular patient or multiplepatients, or as a more sophisticated pager where text messages mayaccompany an alarm when the being monitored physical parameter(s) of aparticular patient or a given number of patients is/are deemed to beirregular and warrants closer scrutiny.

Power consumption is an important consideration in oximetry, since thewireless oximeters are relatively small and yet may require substantialpower to operate their radio transmitters. There is therefore a need forthe wireless oximeters to conserve their energy. For the network of theinstant invention, since each oximeter sensor is programmed tocommunicate only in a given time slot assigned to it in a given timeperiod, the wireless oximeter does not need to be cognizant of whathappens to the other time slots. The wireless oximeter can therefore gointo a sleep or suspension mode to conserve its power when it is not inits communication mode. But during the time that the wireless oximeteris in operation, it is important that it be synchronized with thecommunicators, or at least the communicator that is in range of itssignals, and be able to broadcast the information that it senses fromthe patient to whom its sensor is attached. The time slotted schedulecommunications protocol of the instant invention allows suchconservation of energy due to its deterministic characteristics.

With reference to FIG. 12, the interactions between a wireless oximetersensor and a communicator are shown. The sensor and the communicatorshown in FIG. 12 may be wireless oximeter 22 (Sensor 1) and communicator6 a (CO1), respectively, as shown in FIG. 8. For the communicator CO1,FIG. 12 shows the time slot (0 to T) that the communicator has beenallotted for transmitting its messages. For Sensor 1, FIG. 12 shows asequence of functions that the oximeter goes through duringapproximately the same time period to conserve power.

As shown in FIG. 12, at time 42 a, communicator CO1 is transmitting, forexample the RDD message and other transmissions disclosed with referenceto FIGS. 9 and 10. At the same time 44 a, Sensor 1, which is connectedto a patient, is in its sleep mode. At time 42 b, communicator CO1continues to transmit its data. At time 44 b, Sensor 1 wakes up eitherin response to an internal timer or from the initialization of thesensor to begin collecting the physical parameter(s) from the patient.This wake-up time is referenced as T_(WU) in FIG. 12. At time 42 c,communicator CO1 continues to transmit its data. In the correspondingtime 44 c, Sensor 1 receives the patient data serially from its sensor.At time 42 d, communicator CO1 transmits a signal to a particularwireless oximeter, for example Sensor 1. At corresponding time 44 d,Sensor 1 receives the radio frequency signal from communicator CO1 and,noting that it is a signal specifically identifying it, synchronizes itstiming with that of communicator CO1. Thereafter, at time 44 e, Sensor 1transmits the data that it has obtained from the patient. This data isreceived by communicator CO1 at time 42 e, as designated by the RX WS(receive wireless sensor) signal. Thereafter (after time T),communicator CO1 enters into a receiving mode where it listens to thevarious oximeters and communicators that may be present in the network,for example the RX₁, RX₂ to RX_(M) devices. At approximately the sametime, Sensor 1 goes to its sleep mode (T_(GS)) and stays asleep until itis either waken up by an internal timer or activated to begin monitoringthe physical parameter, for example SP02, of the patient.

By thus putting the wireless oximeter sensor to sleep when it is notmeasuring the physical parameters from the patient, the power requiredfor the oximeter is reduced and therefore the size of the oximeter maybe reduced. On the other hand, the radios of the communicators, whichare mobile units, would remain awake in order to listen in on the othercommunicators, and other devices, that form the nodes in the network.

For the alarm pager aspect of the invention discussed earlier, it shouldbe noted that such pager would only need to listen in on the informationthat is propagating along the network. In other words, a communicatoroperating in the guise of a pager does not need to transmit anyinformation. Thus, a pager communicator does not do the function of acommunicator described thus far. But a communicator does do, as one ofits functions, the paging function by receiving the data beingpropagated along the network and looking for any alarm conditions.Putting it another way, a communicator is bidirectional in terms of itscommunicative functions, whereas the pager does not need to be.

With reference to FIG. 13, a more detailed block diagram of thecommunicator of the instant invention is shown. The same numbers thatwere used for the FIG. 4 block diagram are used herein for the samecomponents. As shown, communicator 6 has a main host board or modulethat has an oximeter module 12 and a radio module 20. In the oximetermodule 12, there is a memory 12 a, a processor controller 12 b that isdedicated for the oximeter module and a sensor circuit 12 c. Sensorcircuit 12 c is connected to a sensor connector 46 to which a sensorattached to a patient may be connected by means of a cable. The radiomodule 20 of the communicator also has its dedicated memory 20 a, adedicated processor controller 20 b, a transceiver 20 c, and an analogcircuit 20 d that drives the signal to an antenna 20 e for transceivingdata to and from the communicator.

On the main host board, there is a memory 10 and a microprocessor 8which controls all of the modules as well as the drivers on the hostboard or module of the communicator. Processor 8 obtains the oximetrydata from the oximeter module or circuit. This data may be communicatedby visual display, audio alarms, wired communications, and RFcommunications. As shown, there are four different drivers 48 a, 48 b,48 c and 48 d. Driver 48 a drives a display 50 that displays for examplethe SPO2 and the pulse rate of a patient, and possibly text messages inaddition, when information more than the SPO2 and pulse rate are desiredor when the communicator is being used as a pager. Driver 48 b drives analarm 52 which triggers when the measured patient parameter is deemednot to be within an acceptable range. Driver 48 c drives an user input54 such as for example a keypad or a pointing device to allow the userto interact with the communicator. Driver 48 d works with a wirecommunications module 56, which in turn has connected thereto acommunication connector 58 that may for example be an RS-232 port or aUSB port as was discussed previously.

The power of the communicator is provided by a power circuit 58 thatregulates the power level of a battery 60. An external power interface62 connects to the power circuit 58 to a power connector 64, so thatexternal power may be provided to either recharge battery 60 or to powerthe communicator from a power outlet, as for example when thecommunicator is connected by cable to a sensor that is attached to thepatient. The software program for the functioning of the communicator isstored in memory 10.

FIG. 14 is an exemplar schematic diagram of the communicator of theinstant invention. As shown, the main communicator printed circuit boardor module 66 is divided into a number of major modules or circuits.These circuits include oximeter module 68, power module 70, displaymodule 72, the main processor 74 and its associated circuits on the PCboard it is mounted to, memory module 76, audio module 78 and radiomodule 80. There are also miscellaneous circuits that include forexample the realtime clock, A/D converter, and external communicationscircuitries. A docking station and a printer (not shown) may also beincluded in the system.

Oximeter module 68 comprises an oximeter PCB (print circuit board) ofthe assignee, designated 68 a, that has a manufacturer reference PN31392B1, or variants of PN 31402Bx or PN 31392Bx. This oximeter boardcommunicates by way of a logic level, full duplex, UniversalAsynchronous Receiver Transmitter (UART) from the P12 connector to thehost processor 74. Power to the oximeter circuit board 68 a is providedby power circuit 70 in the form of regulated 3.3 volt via connector P12through switched capacitor regulator U9. Connector P11 at board 68provides the connection to a connector P14 at main board 66, which isused to connect to a wired oximeter sensor. The signals received fromthe oximeter sensor are routed through board 68 a, and by way ofconnector P12 to processor 74.

Power module 70 is adapted to be powered from multiple sources whichinclude a universal mains AC/DC 9V wall mount power supply, a UniversalSerial Bus (USB) powered at 5V at 500 mA, a user changeable AA (4alkaline disposable batteries at 6V), and custom lithium ionrechargeable batteries at 7.4V. Whichever power is supplied isautomatically arbitrated. The AC/DC 9V power and the USB 5V power enterthrough the general purpose docking/serial communications connector P3.The alkaline and lithium ion rechargeable batteries occupy the sameinternal battery compartment so that one or other can be present at anygiven time and each have their separate connections. The alkalinebatteries are connected four in series by way of connectors P9 and P8,while the lithium rechargeable pack connects through the five-positionconnecter P10. The lithium ion rechargeable pack contains integralcharging control, fuel gauge, and redundant safety circuits. Additionalsignals on P10 are the AC/DC 9V power, USB 5V power plus 7.4V out,ground and 1-1 wire logical interface to the main processor 74 (U21) tocommunicate the charging and fuel gauge information. As shown, all ofthe possible power supplies are diode OR'ed to create a source that canrange between 4.5V and 8.5V before being routed to the main on/off powerMOSFET transistor Q2. The power source is then efficiently converted to2.7V by way of a step down converter/switchable regulator U3. Othersupply voltages of 1.8V and 1.5V are also created by regulators U2 andU1, respectively. The main processor U21 operates from the 2.7V, 1.8Vand 1.5V supplies. The flash and SDRAM memories operate from the 1.5Vsupply. The radio and much of the general purpose I/O operate from the2.7V supply.

The display circuit may comprise a color TFT 3.0 inch LCD displaymanufactured by the Sharp Electronics Company having a manufacturingnumber PN LQ030B7DD01. The display resolution is 320Hx320V. ProcessorU21 provides an integral LCD controller peripheral that is capable ofgenerating a majority of the required timing and LCD control signals.Four additional LCD related circuits (external to processor U21) areshown. Contrast control is provided through digital potentiometer (POT)U12 and commanded by the main processor U21 by way of an I²C two-wirebus. AC and DC gray scale voltages are generated by the gray scale ASICU8. Additional LCD supply voltages of +3V, +5V, +15V and −10V aregenerated by voltage regulators U7 and U10. The light emitting diode(LED) backlighting brightness is controlled by switching regulator U6.The brightness is controlled by the duty cycle of the pulse widthmodulator (PWM) control signal from main processor U21. The LCD displaycontrol signals are brought out from the display module by means of a39-conductive flex flat cable which connects to the connector P6. Thedisplay back light LEDs are brought out from the module with a fourconductive flex flat cable which connects to connector P7.

The main processor 71 (U21) may be an ARM-9 architecture processor fromthe Freescale Company with manufacturing number PN MC9328MX21VM. Thisprocessor has the many onboard peripherals that are needed including forexample the LCD controller, multiple UART ports, I²C ports, externalmemory bus, memory management unit, multiple PWM outputs, low powershutdown modes, key scan and key debounce, to name a few of thecomponents of the processor that are utilized in the communicator of theinstant invention.

In the memory module 76, there are three different types of memories,two 8 Mb×16 SDRAM (Synchronous Dynamic RAM) at 1.8V as designated by U19and U20, one 2 Mb×16 FLASH (non-volatile memory) at 1.8V designated byU22, and one 1 Mb serial EEPROM (Electrically Erasable PROM) at 2.7V.The program code and non-volatile trend data are stored in the Flashmemory. At power-up the program code is transferred from the slowerFlash memory to the higher speed SDRAM to support faster processoroperation. The non-volatile serial EEPROM is used to store system eventlogs, system serial number, and other systems information. Thenon-volatile Serial Flash Memory is used for trend data storage. Thedisplay memory is executed out of the SDRAM memory space.

The audio module 78 supports audio alarms per the 60601-1-8 Alarmstandard for medical devices. Due to the volume and tonal qualitiesdictated by the Alarm standard, a conventional voice coil speaker isused to generate the needed sounds, as opposed to using a piezoelectrictype transducer. Main processor U21 generates a pulse width modulated(PWM) control signal with 11-bits of resolution to control both pitchand volume of the alarm signal. The signal conditioning circuitry U18filters this PWM stream into an analog audio signal which in turn isamplified by a class D audio amplifier U15. U15 differentially drives an8-ohm speaker in the conventional bridge tide load (BTL) configurationfor maximum efficiency.

The radio circuit 80 has a radio module RF1 that may be a single boardtransceiver radio and PCB antenna designed to operate in accordance withthe IEEE 802.15.4 Low Data Rate Wireless Personal Area Network (WPAN)standard. The radio module hardware is supplied by the L.S. Researchcompany, located in Cedarburg, Wis., under the product name Matrixhaving a manufacturing number PN MTX12-101-MTN26. The matrix module is a2.4 GHz 802.15.4 based module that is designed for proprietary andZigBee (a low power, wireless networking standard) data transceiverapplications. The processor and transmitter of the matrix module may bebased on an integrated module such as for example the Texas InstrumentCC2430 chip.

With reference to FIG. 15, a more detailed exemplar wireless fingeroximeter sensor corresponding to that in FIG. 5 is shown. Componentsthat are the same as those in FIG. 5 are labeled the same here. Theoximeter sensor 22 in FIG. 15 is shown to include an oximeter module 26and a radio module 28. In the oximeter module 26 there is a memory 26 a,a controller 26 b and a sensor circuit 26 c. The sensor circuit isconnected to and provides the power to a light source emitter 26 d aswell as a detector 26 e. The light emitter and the detector work incombination to detect or monitor the oxygen saturation in the blood of apatient connected to the emitter and detector. The data collected fromthe patient is stored in memory 26 a. The overall operation of theoximeter module is controlled by controller 26 b.

Radio module 28 has a memory 28 a, a controller 28 b, a transceiver 28c, an analog circuit 28 d and an antenna 28 e. The operation of theradio module 28 for the oximeter sensor device is similar to thatdiscussed with respect to the communicator. However, in most instances,only data that is collected and stored in the oximeter module 26 istransmitted out by the radio transmitter. However, given thattransceiver 28 c is adapted to receive signals as well as to send outsignals, radio module 28 of the oximeter sensor device 22 may be able toreceive a signal from a remote source, for example a communicator, so asto receive instructions therefrom. One such instruction may be a sleepinstruction sent by a communicator to instruct the oximeter to go intothe sleep mode. Another possible instruction may be an awake instructionto wake the oximeter sensor from its sleep mode and to begin monitor theSP02 of the patient. As was discussed with respect to the timedfunctions illustrated in FIG. 12, the oximeter sensor device is adaptedto receive a transmission from a communicator to which it is designated,so that it may be synchronized with the communicator, before datacollected from the patient by the oximeter sensor is transmitted to thecommunicator.

Power is provided to the oximeter and radio modules of the oximetersensor device 22 by power circuit 30, which regulates the power from abattery 30 a. In most instances, the oximeter sensor device 22 is wornby the patient, with the sensor being specifically placed about a digit,such as for example the finger, of the patient. Other types of sensorssuch as for example reflective sensors that are attached to the foreheadof a patient may also be used.

In operation, the processor controller 26 b in oximeter module 26controls an analog sensor circuit that samples the serially incominganalog waveform signal that corresponds to the being measured physicalparameter of the patient. A program is processed by controller 26 b tocompute the digital oximetry data from the sampled analog waveformobtained from sensor circuit 26 c. This digital data is thencommunicated to radio module 28, which transmits the data to thecommunicator that is within its transmission area, so that the data maybe displayed by the communicator. Although the protocol utilized byradio module 28 is the same as that used by the radio module of thecommunicator, there may be hardware differences between the radio modulein the oximeter sensor device and the radio module in the communicator.This is due to for example the omission of the power amplifier and thestrengthening of the antenna because of the size versus performancetradeoffs that are necessary for the oximeter sensor device.

The major transition states of the radio module, based on RFinterrupts—such as for example start, receive and micro controllercontrol—is shown in FIG. 16. As shown, there are four primary states ormodes. These are: idle state 82, receive state 84, transmit state 86,and sleep state 88. There is also an initialization state 90 requiredfor the proper operation of the radio after a hard reset. In the idlestate 82, the radio listens and upon detection of a proper RF signal, itbegins to receive the incoming data. Upon command, the radio enters intothe transmit state 86 where a buffered data packet is communicated overthe RF interface out to the broadcast range of the radio. The sleep mode88 allows the radio to operate at low power without losing its settings.The radio can be turned off in any state.

FIGS. 17-21 are flow charts illustrating the operation of thecommunicator of the instant invention.

In FIG. 17, the radio module enters into the receive mode in step 92.This receive step follows the radio protocol and any additional softwarecontrol. Upon detecting a fiducial signal, the controller of the radiorecords its current time, per step 94. Note that the fiducial signal isdefined in the IEEE 802.15.4 standard as the start frame delimiterdetection signal, and should have a relatively consistent time behavior.In step 96, a determination is made to verify whether the receivedpacket is intended for the particular device, i.e., whether there isproper designation address and format. If the message is not intendedfor this particular radio, then the process returns to an idle state,per step 98. At that time, the message deemed not to be intended for theradio causes the radio to stop receiving data and to discard the data ithas already received, before returning to the idle state. If thedetermination made in step 96 verifies that the message indeed isintended for the radio, then the process proceeds to step 100 where themessage is received and buffered into the local memory of the radio. Instep 102, a determination is made on whether the received message is tobe used for synchronization. If it is not, the process proceeds to step104 where the message is sorted. But if the message indeed is meant forsynchronization, then the process proceeds to step 106 where the slottimer is updated based on the time of the fiducial signal, before themessage gets sorted in step 104. Thereafter, the message is bufferedappropriately in step 108 so that it may be serially transmitted to thehost of the radio. Thereafter, the radio returns to its idle state perstep 98.

FIG. 18 is a flowchart illustrating the transmit process of the radio ofthe communicator. The radio starts transmitting upon command from theradio micro-controller. This is step 110. In this step, themicro-controller will signal the start of its time slot based upon thescheduling and the synchronized timing. Upon the start of a slot, theradio may update its slot timer, per step 112. This may be important ifthere is a single node in the network, (i.e., the communicator is not inthe transceiving range of other communicators but is within thebroadcast range of the wireless oximeter sensor), and the initializationprotocol requires for regular broadcasting of messages. In step 114, adetermination is made on whether there is data to be transmitted for agiven time slot. If there is not, the process returns to the radio idlestate, per step 116. If there is, the data is transmitted per step 118.In step 120, a determination is made on whether the time slot is longenough for another transmission. If it is, the process returns to step114 to retrieve additional data for transmission. The process continuesso long as there is enough time for transmitting more messages. If it isdetermined that there is no longer enough time for a next transmissionin step 120, the process returns the radio to its idle state, per step116, where the radio awaits the next transmit, receive or sleepinstruction.

The aggregate and broadcast processes for the communicators areillustrated in the flow charts of FIGS. 19 and 20, respectively. In FIG.19, the host processor of the communicator receives the RDD message, orother aggregate and forward type messages, from the radio, per step 122.The received data is then compared with the previously stored, or localcopy of the message stored in the memory of the radio, per step 124. Instep 126, a determination is made on whether the receive data is newerthan the previously stored data. If it is, the local memory is updatedwith the received RDD message per step 128. The display on thecommunicator may be updated per step 130. The process then stops perstep 132 until there is a next start. If in step 126 it is determinedthat the data received is not newer than the previously stated data, theaggregate process exits to step 132 to await the next incoming RDDmessage.

FIG. 20 is a flow chart illustrating the forward process for thecommunicator of the instant invention. Per step 134, the RDD table(which also includes the HS data and similar aggregate and forwardmessages) is updated with the local pulse oximetry data. In step 136,any new local pulse oximetry data is retrieved and readied. In step 138,the RDD message is updated. The process then exits per step 140.

In FIG. 21, the processing steps for aggregating and forwarding the datato the radio module from the main processor of the communicator isillustrated. Starting at step 142, the data for the radio module isupdated. Thereafter, in step 144, the messages are queued for the radiomodule. A decision is made on whether there is additional data in step146. If there is, the additional data is serially transmitted to theradio module per step 148. The process continues until a determinationis made, per step 146, that there is no more data to be routed to theradio. At which time, the process is routed to step 150 and theaggregating and forwarding process ends.

FIG. 22 is a flow chart that illustrates the operations of the wirelessoximeter. So that power is conserved, as was noted above, the wirelessoximeter sensor begins in a radio sleep mode. The process thereforebegins at step 152 where the oximeter is awaken by either an externalsignal or an internal timer interrupt, as was discussed previously. Theradio of the oximeter then goes into an idle state per step 154. Fromthe idle state, the radio may receive data, be synchronized and returnsto the idle state. These processes start with step 156 where the startframe delimiter (SFD) is reviewed to capture the time, per discussionwith reference to FIGS. 11 and 12. If it is determined that the SFD isnot for the oximeter in step 158, then the process returns to the idlestate in step 154 to await the SFD that designates or identifies theoximeter sensor as the one. If the oximeter determines that it is thecorrect sensor to be communicating with the communicator, the processproceeds to step 160 where it receives the message. If the message isdetermined to be the synchronization message, per step 162, then theslot timer is updated per step 164 to synchronize the oximeter with thecommunicator. The process then proceeds to step 166 where the messagesoncoming are buffered. The same buffering process also takes place ifthe message is determined not to be a synchronization message.Thereafter, the process returns to the radio idle state, per step 168.

The oximeter remains in the idle state until a start RF transmissioninterrupt or command is received per step 170. At that time, the slottimer is updated per step 172. In step 174, the process determineswhether there is data for transmission. If there is, the data istransmitted per step 176. A determination is next made, per step 178, onwhether there is enough time for transmitting the next message. If thereis, the process returns to the step 174 to retrieve the next message,and transmits the retrieved message per step 176. The process repeatsuntil it is determined, per step 178, that there is no longer enoughtime for the next message. At which time the process returns to the idlestate per step 180. The process also goes into the idle state if it wasdetermined in step 174 that there was no data for transmission. Afterthe idle state, the process may receive further commands per step 182.Thereafter, as the radio and oximeter are independently powdered, toconserve power, the radio is put to sleep per step 184 until it isawakened.

It should be appreciated that the present invention is subject to manyvariations, modifications and changes in detail. For example, eventhough the disclosed network, system and devices have been discussedwith reference to a medical instrumentation environment, it should beappreciated that such network, system and devices are equally adaptableto operate in a non-medical setting. Thus, it is the intension of theinventors that all matter described throughout this specification andshown in the accompanying drawings be interpreted as illustrative onlyand not in a limiting sense. Accordingly, it is intended that theinvention be limited only by the spirit and scope of the hereto appendedclaims.

1. In a wireless communications network having a plurality oftransmitting and receiving devices, a method of conveying informationrelating to physical attributes of a patient remotely, comprising thesteps of: a) associating at least one wireless sensor device with apatient for detecting at least one physical attribute of the patient,said sensor device including at least a transmitter; b) transmittingpatient data corresponding to the detected physical attribute out ontothe network; c) locating a first communicator within transmission rangeof said sensor device, said first communicator having a transceiveradapted to receive the patient data transmitted from said sensor device;d) broadcasting from said first communicator the received patient dataout onto the network; and e) establishing communication between at leasta second communicator and said first communicator, said secondcommunicator not in direct communication with said wireless sensordevice, said second communicator having a second transceiver adapted toreceive the patient data broadcast by said first communicator.
 2. Methodof claim 1, wherein said step (e) further comprises the step of:locating said second communicator to be within the broadcasting range ofsaid first communicator so that said second communicator is in directcommunication with said first communicator.
 3. Method of claim 1,wherein when said second communicator is outside the broadcasting rangeof said first communicator, said step (e) further comprises the step of:locating said second communicator within the broadcast range of at leastone other communicator that is located within the broadcasting range ofsaid first communicator or said sensor so that said second communicatorreceives the patient data received by said one other communicator fromeither said first communicator or said sensor and thereafter broadcastby said one other communicator.
 4. Method of claim 1, wherein said step(b) further comprises the steps of: sending the patient data to anyother first communicator located within the broadcast range of saidsensor device; and sending the patient data through said any othercommunicator for reception by said second communicator.
 5. Method ofclaim 4, further comprising the steps of: storing the patient data insaid any other communicator as the patient data is received by said anyother communicator; and propagating the stored patient data from saidany other communicator along the network.
 6. Method of claim 1, whereineach of said first and second communicator comprises a memory forstoring patient data that it receives, the method further comprising thestep of: updating the stored patient data in the memory of each of saidcommunicators as new patient data is received so that only the mostrecent patient data stored is broadcast from said each communicator. 7.Method of claim 1, wherein said sensor device comprises a portableoximeter worn by or attachable to the patient; wherein said step (a)comprises the step of: detecting the SPO2 of the patient for saidpatient attribute.
 8. Method of claim 1, wherein each of saidcommunicators comprises a mobile oximeter, the method further comprisingthe step of: displaying the received patient data on at least one ofsaid communicators.
 9. Method of claim 1, further comprising the stepsof: associating multiple wireless sensor devices with respectivepatients; wherein for each of the multiple sensor devices detecting atleast one physical attribute from the patient associated with said eachsensor; and transmitting the physical attribute detected by said eachsensor device; locating a plurality of communicators in the network;wherein, for each of said communicators, receiving the patient datatransmitted from any one of said multiple sensor devices if said eachcommunicator is located within the transmission range of said any onesensor device; and assigning said multiple sensors and plurality ofcommunicators respective synchronized time slots so that said sensordevices and communicators are respectively adapted to effect scheduledtransmission, reception and/or broadcasting of signals and/or data. 10.Method of claim 1, further comprising the step of: time synchronizingthe respective operations of said sensor device and each of saidcommunicators with a communications schedule for the transmission,reception and/or broadcasting of signals and/or data.
 11. In a wirelessnetwork having a plurality of nodes, a method for disseminatinginformation of a patient, comprising the steps of: a) associating atleast one first type node with the patient for monitoring physicalattributes of the patient, said first type node including a detectorthat detects at least one physical attribute of the patient and atransmitter that transmits the detected physical attribute as patientdata out to the network; b) locating a plurality of second type nodesnot directly associated with the patient in the network, each of saidsecond type nodes adapted to receive signals and/or data from said firsttype node when moved to within broadcast range of said first type node,each of said second type nodes further adapted to receive signals and/ordata from other second type nodes and to broadcast signals and/or dataout to the network; c) moving one of said second type nodes to withinthe broadcast range of said first type node to receive the patient dataoutput from said first type node; and d) broadcasting from said onesecond type node the received patient data out to the network so thatany other second type node located within broadcast range of said onesecond type node could receive the patient data output by said firsttype node.
 12. Method of claim 11, comprising the step of: storingpatient data in each of said second type nodes as the patient data isreceived and passed along by said each second type node for propagationalong the network.
 12. Method of claim 11, wherein said first type nodecomprises a portable oximeter worn by or attachable to the patient, andwherein said step (a) comprises the step of: detecting as said patientattribute the SPO2 of the patient.
 13. Method of claim 11, wherein eachof said second type nodes comprises an oximeter having at least atransceiver for receiving and transmitting signals and/or data from andto, respectively, nodes in the network; the method further comprisingthe step of: displaying the received patient data on at least one ofsaid second type nodes.
 14. Method of claim 11, further comprising thestep of: assigning said first type node and second type nodes respectivesynchronized time slots to effect scheduled transmission, receptionand/or broadcasting of signals and/or data.
 15. Method of claim 11,further comprising the step of: time synchronizing said first type nodeand each of said second type nodes with a communications schedule forthe transmission, reception and/or broadcasting of signals and/or data.16. In a wireless network having a plurality of nodes, a method fordisseminating information of a patient, comprising the steps of: a)associating each of multiple first type nodes with a particular patientfor monitoring physical attributes of the particular patient, said eachfirst type node including a detector that detects at least one physicalattribute of the particular patient and a transmitter that transmits thedetected physical attribute as patient data out to the network; b)positioning in the network a plurality of second type nodes not directlyassociated with any patient; c) configuring each of said second typenodes to receive signals and/or data from said first type nodes whenmoved to within broadcast range of any of said first type nodes, and toreceive signals and/or data from other second type nodes and broadcastsignals and/or data out to the network; d) locating one of said secondtype nodes to within the broadcast range of any said first type node toreceive the patient data output from said any first type node; and e)broadcasting thereafter from said one second type node the receivedpatient data out to the network so that any other second type nodelocated within the broadcast range of said one second type node couldreceive the patient data output by said any first type node.
 17. Methodof claim 16, wherein said first type nodes each comprise a portableoximeter worn by the patient; wherein said step (a) comprises the stepof: detecting the SPO2 as said one patient attribute.
 18. Method ofclaim 16, wherein each of said second type nodes comprises an oximeterhaving at least a transceiver for receiving and transmitting signalsand/or data from and to, respectively, nodes in the network, the methodfurther comprising the step of: displaying the received patient data onat least one of said second type nodes.
 19. Method of claim 16, furthercomprising the step of: assigning respective synchronized time slots tosaid first type nodes and second type nodes to effect schedulednon-interfering transmission, reception and/or broadcasting of signalsand/or data for the nodes.
 20. Method of claim 16, further comprisingthe step of: storing the patient data in each of said second type nodesas the patient data is received and passed along by said each secondtype node for propagation along the network.